This invention relates generally to a pump that combines the functions of a boiler feed pump and condensate pump and more particularly to a combined boiler feed pump and a condensate pump having a motor and a common shaft, and adapted to be mounted in a pipeline in an inline configuration with the motor driving the common shaft being housed entirely within the pump casing to provide a sealless pump.
The usual powerplant steam boiler system includes a feed pump for feeding water to the boiler to replace the water that is converted into steam and a separate condensate pump for extracting condensate from the condenser and placing it under pressure prior to feeding it to the feed pump. A steam condenser operates at a vacuum and the pressure in the inlet of the condensate pump is either at a very low positive pressure or a negative pressure (vacuum). The usual feed pump cannot operate properly at a low inlet pressure and therefore a condensate pump is required to create sufficient pressure on the condensate before delivering it to the inlet of the boiler feed pump.
The foregoing illustrates limitations known to exist in present steam boiler systems. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.